1491327891 has 12 divisors (see below), whose sum is σ = 2206680840. Its totient is φ = 969969120.

The previous prime is 1491327847. The next prime is 1491327911. The reversal of 1491327891 is 1987231941.

1491327891 is a `hidden beast` number, since 1 + 491 + 3 + 2 + 78 + 91 = 666.

It is not a de Polignac number, because 1491327891 - 2¹³ = 1491319699 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1491327191) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2020401 + ... + 2021138.

It is an arithmetic number, because the mean of its divisors is an integer number (183890070).

Almost surely, 2^1491327891 is an apocalyptic number.

1491327891 is a deficient number, since it is larger than the sum of its proper divisors (715352949).

1491327891 is a wasteful number, since it uses less digits than its factorization.

1491327891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4041586 (or 4041583 counting only the distinct ones).

The product of its digits is 108864, while the sum is 45.

The square root of 1491327891 is about 38617.7147304187. The cubic root of 1491327891 is about 1142.5039582847.

The spelling of 1491327891 in words is "one billion, four hundred ninety-one million, three hundred twenty-seven thousand, eight hundred ninety-one".